With scale expansion and complication of a storage environment due to an increase of company data, thin provisioning that utilizes virtual volumes (hereinafter sometimes referred to as the virtual volumes), which themselves do not have storage areas, has been widely used for the purpose of facilitation of operation management and integration of the storage environment.
The thin provisioning presents virtual volumes to a host computer; and when the host computer makes write access to a virtual volume, a physical storage area for actually storing data is allocated to the virtual volume. Therefore, it is possible to efficiently use storage areas in a storage apparatus, while presenting the volumes, whose capacity is not less than that of the storage areas in the storage apparatus, to the host computer.
Specifically speaking, the thin provisioning defines one or more logical volumes in the storage areas provided by one or more hard disk devices (HDDs: Hard Disk Drives). Moreover, one or more logical volumes constitute one storage pool and one or more virtual volumes are associated with each storage pool. When the host computer makes write access to a virtual volume, a specified size unit of the storage area (the storage area of this size will be hereinafter referred to as the page) is allocated from any of the logical volumes in the storage pool associated with that virtual volume to the relevant segment of the write-accessed virtual volume.
Furthermore, Patent Literature 1 discloses a computer system in which objects in a file system, to which block access can be made, and a virtualization module that cooperates with the file system in order to manage the objects, are provided in a storage apparatus handling both file accesses and block accesses. Patent Literature 1 describes that virtual volumes for operating databases and virtual volumes for operating the file system can be managed integrally by one storage apparatus. Particularly, a storage administrator can set a capacity limitation value for each virtual volume, each directory in the file system, or each user.
Furthermore, Patent Literature 2 discloses integrated capacity management of the entire computer system by executing capacity limitation processing (quota limitation processing) in a plurality of file systems in cooperation with each other, while such capacity limitation processing has been executed in only one file system in the conventional art.